Timms Histochemistry

Does anyone have suggestions for eliminating black, particulate sludge from my
slides after Timms staining? Every square inch of glassware, stir bars, etc.
has been acid cleaned and I am only using glass distilled water. When I add
the silver nitrate to the developer I am getting a cloudy precipitate. Please
advise with any and all ideas.
Thanks,
Nancy Lemke